1. Field of the Invention
The invention relates to a light-emitting device in which light from a light source having an LED element mounted by flip-chip connection is incident on a light guide plate. In addition, the invention relates to a planar light-emitting device in which light from a light source having an LED element mounted by flip-chip connection is incident on a light guide plate. Also, the invention relates to a light source including a light-emitting element sealed with glass, a method of manufacturing the same and a light-emitting device provided with the light source.
2. Related Art
A light source is known in which an LED element mounted on an element mounting substrate is sealed with an inorganic material such as glass, etc. (see, e.g., WO 2004/82036). In the light source described in WO 2004/82036, plural LED elements are mounted on an element mounting substrate by flip-chip connection, a hot pressing process is performed on glass, and the individual LED elements are thereby collectively sealed with the glass. The light source is in a cube shape and light is emitted from the upper and side surfaces thereof. A direction of an optical axis is perpendicular to the element mounting substrate.
Meanwhile, a light-emitting device using a light guide plate is known in which plural rows of cylindrical bore shaped or concave light incident portions are provided on a rear surface of the light guide plate in the vicinity of at least one side surface so as to be parallel thereto (see, e.g., JP-A 2005-276491). In this light-emitting device, the light incident portions are formed in a thickness direction of the light guide plate and a plane emission light source for laterally emitting light is used. In detail, the light source has concentric inclined surface portions on inner and outer surfaces at the upper portion thereof, light from a semiconductor light-emitting element is totally reflected at the inclined surface portion of the inner surface and the critical angle is exceeded at the inclined surface portion of the outer surface, and the light is emitted radially in all directions.
A light-emitting device using a light guide plate is known in which plural rows of cylindrical bore shaped or concave light incident portions are provided on a rear surface of the light guide plate in the vicinity of at least one side surface so as to be parallel thereto (see, e.g., JP-A 2005-276491). In this light-emitting device, the light incident portions are formed in a thickness direction of the light guide plate and a plane emission light source for laterally emitting light is used. In detail, the light source has concentric inclined surface portions on inner and outer surfaces at the upper portion thereof, light from a semiconductor light-emitting element is totally reflected at the inclined surface portion of the inner surface and the critical angle is exceeded at the inclined surface portion of the outer surface, and the light is emitted radially in all directions.
In addition, as a light-emitting device using a light guide plate, a lighting system is known which is provided with plural LED light sources arranged on a circuit board and a light guide plate for guiding light of the LED light sources as illumination light to be incident from an incidence plane to a light exit surface, and in which the light guide plate is composed of upper and lower light guide plates, the lower light guide plate has a concave portion for guiding output light from each LED light source into the light guide plate, and the LED light source is arranged in the vicinity of an aperture plane of the concave portion (see, e.g., JP-A 2007-165064).
A conventional light source is known in which a GaN-based LED element is mounted on an element mounting substrate formed of ceramic and the LED element is sealed with a glass material on the element mounting substrate (see WO 2004/82036). Plural LED elements are mounted on the element mounting substrate, the individual LED elements are collectively sealed with a plate-like glass material, and the element mounting substrate and the glass material are subsequently cut by dicing, thereby manufacturing the light source. The light source manufactured as described above is in a state in which the LED elements are sealed with a glass sealing portion in a rectangular parallelepiped shape.
A light-emitting device using a light guide plate is known in which plural rows of cylindrical bore shaped or concave light incident portions are provided on a rear surface of the light guide plate in the vicinity of at least one side surface so as to be parallel thereto (see, e.g., JP-A 2005-276491). In this light-emitting device, the light incident portions are formed in a thickness direction of the light guide plate and a plane emission light source for laterally emitting light is used. In detail, the light source has concentric inclined surface portions on inner and outer surfaces at the upper portion thereof, light from a semiconductor light-emitting element is totally reflected at the inclined surface portion of the inner surface and the critical angle is exceeded at the inclined surface portion of the outer surface, and the light is emitted radially in all directions.
In addition, as a light-emitting device using a light guide plate, a lighting system is known which is provided with plural LED light sources arranged on a circuit board and a light guide plate for guiding light of the LED light sources as illumination light to be incident from an incidence plane to a light exit surface, and in which the light guide plate is composed of upper and lower light guide plates, the lower light guide plate has a concave portion for guiding output light from each LED light source into the light guide plate, and the LED light source is arranged in the vicinity of an aperture plane of the concave portion (see, e.g., JP-A 2007-165064). Meanwhile, a light-emitting device having an LED light source and using a polarizing element without using a light guide plate is also known (see, e.g., JP-A 2005-44661).